Liner for ball mills



y 1939- E. M. HOUGH'TON 2,158,187

LINER FOR BALL MILLS Filed March 27 1957 Patented May 16, 1939 PATENT OFFICE LINER FOR BALL MILLS Edward M. Houghton, Cobalt, Ontario, Canada,

assignor to M. J. OBrien,

tario, Canada Limited, C'obalt, 0n-

Application March 27, 1937, Serial No. 133,317

5 Claims.

The principal objects of this invention are to provide a liner for ball mills which will increase the grinding efficiency of the mill by more effectively holding the balls in concentrated groups around the inner face of the liner to engage with the mass of balls lying loosely in the mill and between the engaging surfaces of which the major grinding of the ore or other material to be pulverized takes place and which will more effectively protect the liner from wear.

A further and important object is to devise a form of liner which will present the maximum of hardened wear-resisting surfaces to the abrasive action of the balls.

A still further object is to devise a very simple formof liner structure which may be made of comparatively inexpensive material and which may be easily and quickly replaced.

The principal feature of the invention consists in the novel construction of a plurality of cast metal liner sections which may be termed blocks adapted to be fitted together against the inner wall of the mill, each block having a plurality of cavities-therein which are divided by inwardly projecting ribs to form a plurality of interconnected pockets adapted to retain a quantity of loose grinding media in such a manner that such media will project beyond the liner structure and form contact surfaces for engaging the loose mass of grinding media contained in the mill.

In the accompanying drawing Figure 1 is a small cross sectional view of a ball mill illustrating the manner of arranging therein a plurality of liner blocks constructed in accordance with this invention.

Figure 2 is an enlarged top or inner side plan view of a portion of one of my improved liner blocks.

Figure 3 is an enlarged sectional plan view of a portion of one of my liner blocks showing the inside of the cavity taken from the bottom or outer side of the block.

Figure 4 is a perspective sectional view of a portion of a block as illustrated in Figure 3, the bottom or base of the cavity being removed.

Figure 5 is an enlarged cross sectional view of part of two adjacent blocks arranged as positioned in a mill, the upper one being a section through the line 5-5 of Figure 2 and the lower one being through the line 55' of Figure 2.

Figure 6 is a fragmentary part sectional side elevational view on the line 6-6 of Figure 1.

In the operation of ball mills it is important that the loose grinding media, usually cast iron balls, be carried to a certain extent with the mill in its rotation so that a tumbling or cascading action will be constantly maintained and to accomplish this result it is necessary that there be some form of inwardly projecting abutments from the inner wall of the mill. Many forms of 5 toothed blocks have been used but owing to the expensive material required for such uses the maintenance cost is very high.

In the present invention I propose to use cast steel or cast iron blocks I which are formed with cavities 2 which are adapted to hold a variable quantity of the loose grinding media and it is an important feature of the present invention to provide means in association with each cavity for definitely trapping or wedging the ball units therein with certain of the trapped units projecting more or less from the inward side of the cavity and thus forming abutments to engage the loose media in the mill and definitely enhancing the'wearing quality of the liner and increasing the efliciency. The inner wall surfaces of the cavities may converge toward the top or inner side or they may be parallel.

In the construction of blocks herein shown the cavities at the bottom or outward side are of substantially rectangular form, and ribs or claws 3 are formed in the side walls which project inwardly and these ribs preferably converge inwardly toward the centre of the main cavity and form a central opening 4 on the inward side which is substantially rectangular and is of t a size sufficient to permit the balls or other grinding media to enter.

The converging ribs 3 serve to subdivide the main cavity 2 to form upwardly converging intercommunicating pockets 5 which pierce the top surface of the block at spaced intervals around the central opening 4. The openings 6 at the top of the pockets 5 are formed of lesser diameter than the diameter of the grinding balls and are here shown smaller than the inlet openings 4 so that the innermost balls entrained in the pockets will project partly through the said openings and thus present protuberances which will engage the mass of balls or other media on the 45 mill, and as the entire surface of the mill will be interspersed with these protuberances and others will become wedged in the openings 4 a rough propelling surface and hard efiective grinding surface is presented to co-operate with the loose grinding media in the mill in an effective grinding operation.

The balls projecting from the cavities, of the liner blocks, engaging the loose grinding media, protect the top or innersurface of the liner blocks 5 from destructive abrasion of said loose media so that the said liners will not wear quickly.

Further the construction of the blocks with the peculiar shaped cavities enable the structure of the blocks being of substantially uniform cross section and such cross section is comparatively thin, consequently in the casting of the metal the major area of the surfaces exposed to the contact of the grinding media will be of a hard crystalline formation, as occurs in cast metals, and ferrous substances so cast will resist wear to a very high degree with the result that a liner so constructed will have very long life.

I have shown the blocks formed each with a double row of cavities but it must be understood that such blocks may be made any desirable width and with any desirable number of rows of cavities. The blocks may be formed with end flanges l which abut adjacent flanges thus forming be tween each circumferential section of liners a groove in which an expansion ring? or other device may be placed to secure the sections in place, or bolts 8 may be used.

It will be appreciated that the material of the liner blocks will wear but as they wear they continue to present edge surfaces to engage and grip the loose grinding media but as the cavities formed in such blocks flare downwardly there will always be a mass of the loose grinding media wedged therein and though such media will loosen and be released in some of these cavities they will again fill and continue to function to hold such media so that there willbe protuberances to form engaging surfaces to continue the grinding action of the mill.

What I claim as my invention is:

l. A liner for ball mills comprising metal blocks each having a cavitytherein, the inside walls of which converge to an opening, and ribs extending radially inward from said converging wall and flaring inwardly, subdividing the interior of said cavity into a plurality of cavities each converging to an individual opening, the inward edges of said ribs being spaced to form a central opening.

openings and communicating with all the pockets 10 of each group and forming a charging opening for the entry of balls to said pockets.

3. A lining section for ball mills having a group of pockets each having an opening through the grinding face smaller than the grinding balls 15 and an inlet in the grinding face leading to all the pockets of said group and adapted to permit the entry of the grinding balls.

4. A liner for ball mills comprising metal blocks adapted to be fitted together on the inside of 20 the mill and each having a plurality of cavities each of rectangular formation at the bottom or outward side, and ribs extending: inwardly from each of the side walls of the cavities and converging toward the inner face of the block form- 25 ing a central orifice and a plurality of smaller orifices arranged in'diagonally opposite pairs, the ribs of each cavity being spaced apart transversely to provide communication between said central and diagonal orifices. 30

5. A liner for ball mills comprising cast metal blocks having their longitudinal side walls flared inwardly, and transverse walls spaced apart flared inwardly forming a plurality of inwardly converging pockets, said side walls and transverse 36 walls having inwardly flaring ribs dividing the inward portion of each of said cavities intoa plurality of intercommunicating converging pockets, said pockets having orifices leading through the inner face of the block and an orifice being 40 formed between the converged inner ends of said ribs.

EDWARD M. HOUGI-ITON. 

